本文教程操作环境:windows7系统、Python 3.9.1,DELL G3电脑。
1、概念
numpy.where(condition [,x,y])函数返回满足给定条件的输入数组中元素的索引。
2、参数
condition
3、返回值
返回out
代码1:
<p style="line-height: 1.75em"><span># Python program explaining # where() function import numpy as np np.where([[True, False], [True, True]], [[1, 2], [3, 4]], [[5, 6], [7, 8]])<br /></span></p>
输出:
<p style="line-height: 1.75em"><span>array([[1, 6], [3, 4]])<br /></span></p>
代码2:
<p style="line-height: 1.75em"><span># Python program explaining # where() function import numpy as np # a is an array of integers. a = np.array([[1, 2, 3], [4, 5, 6]]) print(a) print ('Indices of elements <4') b = np.where(a<4) print(b) print("Elements which are <4") print(a[b])<br /></span></p>
输出:
<p style="line-height: 1.75em"><span>[[1 2 3] [4 5 6]] Indices of elements <4 (array([0, 0, 0], dtype=int64), array([0, 1, 2], dtype=int64)) Elements which are <4 array([1, 2, 3])<br /></span></p>
以上就是Python中numpy.where()函数的使用方法。
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